Administration of medication contained in sealed reservoirs often involves a penetration of the reservoir seal. For example, people with diabetes using pen injection systems for self-administration of insulin or GLP-1 attach a needle assembly comprising an injection needle to the pen injector, whereby a reservoir closure is transpierced by the injection needle, and subsequently operate the pen injector to expel a dose of medication through the injection needle and into the body.
A needle assembly for an injection device typically also comprises a skirt provided with an internal threaded section for engagement with a mating external thread on the injection device. When the needle assembly is properly attached fluid communication to the reservoir interior is established and the injection needle can be inserted through the skin of the user. To avoid the risk of contamination from growth of bacteria around the needle tip between uses it is conventionally recommended that the needle assembly be discarded after a single use. However, some people ignore this recommendation and consciously decide to use the same needle assembly again and again.
WO 2014/064100 (Novo Nordisk A/S) discloses an injection system comprising an injection device and a needle cannula, where a distal portion of the needle cannula is accommodated in a chamber when not in use, and where the chamber contains a cleaner, such that multiple use of the same needle cannula entails a reduced risk of contamination from bacteria. Even with such a solution, however, excessive use of the needle cannula may lead to other issues such as e.g. needle clogging and/or needle abrasion. Furthermore, the risk of cross-contamination arising from different users sharing the same needle cannula by using it on their respective injection devices is still present.
US 2014/0052102 (Sanofi-Aventis Deutschland GmbH) and US 2014/0303555 (Sanofi-Aventis Deutschland GmbH) both disclose a dispense interface for use with a drug delivery device which has a lockout mechanism that prevents reuse of the dispense interface after it has been used with a drug delivery device. In the former the dispense interface comprises a receiving opening configured to receive a connecting part of the drug delivery device in a spread condition of the receiving opening and to block receiving the connecting part in a relaxed condition of the receiving opening, and a spreader configured to spread the receiving opening in the spread condition. During initial attachment of the drug delivery device to the dispense interface the spreader is displaced, such that upon subsequent detachment of the drug delivery device the receiving opening automatically changes to the relaxed condition. However, the spreader is a separate element which is displaced to an inactive position during attachment of the drug delivery device, i.e. the solution requires an additional constructional part which is rendered useless upon the initial use of the dispense interface, adding to the production costs.
In the latter the process of attaching the dispense interface to the drug delivery device mechanically moves a lockout element such that once the dispense interface is detached the lockout element mechanically blocks a reattachment of the dispense interface to any drug delivery device of the same kind.
None of these prior art lockout solutions appear to be useable for conventional injection systems within diabetes care, where e.g. a pen type injection device is provided with a threaded interface and configured to receive an injection needle assembly with a mating thread, as they are both designed for use in a system where the drug delivery device and the dispense interface are attached, respectively detached, by simple axial relative motion.